1. Field of the Invention
The invention discloses a USB electronic device and specially relates to a slim USB electronic device.
2. Description of the Prior Art
With the progress in the information technology (IT) industry, portable electronic devices become more and more popular. Some of them, such as a flash drive or a small memory card, are capable of communicating with host (PC or notebook computer) through specific transmission interfaces, in which the universal serial bus (USB) is the most popular one. Because the USB is one of the most popular I/O interfaces in current personal computers, many electronic devices adopt USB as their transmission interface. The advantage of utilizing the USB is that it reduces the usage of a card reader for portable devices with different I/O interface.
Conventionally the connector for the USB electronic device is separated from the circuit board, and fabricated together by a weld. Because the USB connector's limitations, however, the USB electronic device will become too thick to be portable. Referring to FIG. 1, the housing 100 of the USB connector will influence and increase the volume and thickness of the electronic device. In order to reducing the thickness of all electronic elements among the electronic device as possible, the most regular solution is to improve the USB connector's structure, or to apply a design without connector for thinning out the electronic device. Referring to FIG. 2A and FIG. 2B, Taiwan patent number 570242 discloses a USB storage device, therein the connector 202 is extended from the circuit board and enclosed in an upper housing 200 and a lower housing 201. By utilizing the contacts of a USB receptacle to touch the metal film 204 electroplated directly on the connector 202, the USB storage device could establish an electric loop with the host. However, as the connector 202 inserts and pulls out over and over again, the metal film 204 becomes easier to peel off, resulting in the USB storage device being unable to be used. Besides, most areas of the connector 202 are exposed from the device housing, making the contacts (formed of metal films) short circuit easier by external matter which decrease the electronic device's life.
FIG. 3 illustrates the simplified structure of a small USB connector disclosed in Taiwan patent number 565026, therein connector 30 and circuit board 31 are manufactured whole in one and placed in the lower housing 38. The upper housing 37 merely covers parts of the connector 30 and forms the device's housing with the lower housing 38. In addition, four metal strips 33 are adhered on the connector 30 as the contacts for communicating with an USB receptacle (not shown). Although this structure overcomes the problem that the metal film peels off easily, the connector 30 is still exposed to too external matter. Further, because it's necessary to drill on the connector 30 before adhering the metal strips 33, and a metal housing 39 shaped of U letter is also needed for protecting the connector 30, the structure of the USB electronic device becomes more complicated and harder to fabricate, resulting in difficulties in reducing production costs.
According to the above descriptions, the foregoing two inventions may achieve the goal for a slim USB electronic device, but there are still some disadvantages to overcome. Therefore, there is need to further reduce the thickness of the USB connector and the thickness of the USB electronic device, to overcome the foregoing disadvantages, and provide more protection for the connector (especially contacts of USB electronic device).